Semiconductor package having ultra-thin thickness and method of manufacturing the same

ABSTRACT

A semiconductor package having an ultra thin thickness and a method of manufacturing the same are provided. The ultra thin semiconductor package comprises a circuit board in which a through hole is formed. A semiconductor chip is located in the through hole and a connecting element electrically connects the circuit board and the semiconductor chip. An epoxy molding compound (EMC) covers the semiconductor chip and the connecting element and a supporter having a thermal expansion coefficient similar to the EMC is attached inside the through hole on a lower surface of the semiconductor chip. An external connecting terminal is attached to at least one side of the circuit board. Because of the inclusion of the supporter, warpage of the semiconductor package resulting from the curing of the EMC is prevented.

This application is a Divisional of U.S. patent application Ser. No. 10/982,361, filed on Nov. 3, 2004, which claims the priority of Korean Patent Application No. 2003-79597, filed on Nov. 11, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor package and a method of manufacturing the same, and more particularly, to an ultra-thin semiconductor package having a supporter that prevents warpage of the semiconductor package and a method of manufacturing the same.

2. Description of the Related Art

Smaller and thinner semiconductor packages such as a chip scale package, a micro ball grid array package, and an ultra-thin semiconductor package have recently been developed.

An ultra-thin semiconductor package is disclosed in U.S. Pat. No. 6,395,579. The structure of an ultra-thin semiconductor package will now be described.

FIG, 1 is a cross-sectional view of a conventional semiconductor package 100 having a through hole.

Referring to FIG. 1, a circuit board 10 has a through hole 12 with a size similar to a chip and a semiconductor chip 30 is located in the through hole 12. The semiconductor chip 30, which is located in the through hole 12, is electrically connected to a circuit pattern 18 of the circuit board 10. Predetermined portions of the semiconductor chip 30 and the circuit board 10 are molded by an epoxy molding compound (EMC) 50 composed of a resin material. In addition, a conductive ball 60 is attached to a lower surface of the circuit board 10.

The semiconductor package 100 can have a thickness similar to the height of the semiconductor chip 30.

A resin material is generally used for the EMC 50, covering predetermined portions of the semiconductor chip 30 and predetermined portions of the circuit board 10.

The EMC 50 is formed by spreading the resin material on the semiconductor chip 30 and the circuit board 10 and then curing the resin material at a predetermined temperature. The EMC 50 contracts in the curing process.

However, as is well known to those skilled in the art, the EMC 50 formed of the resin material and the semiconductor chip 30 formed of a silicon material have different thermal expansion coefficients, and thus, they contract by different amounts in the curing process. Therefore, as illustrated by W in FIG. 1, the semiconductor chip 30 and the EMC 50 may warp due to the relatively low contraction rate of the semiconductor chip 30. This is called warpage.

A degree of warpage d of the semiconductor chip 30 and the EMC 50 may be 100 to 400 μm. The warpage causes the height of the semiconductor package to increase. Thus, an ultra-thin semiconductor package would not be obtained. Furthermore, cracks may occur due to the warpage of the semiconductor package.

SUMMARY OF THE INVENTION

The present invention provides a semiconductor package having an ultra-thin thickness and a method of manufacturing the same in such a way that warpage of the semiconductor package is prevented.

According to an aspect of the present invention, there is provided an ultra thin semiconductor package comprising a circuit board having a through hole; a semiconductor chip located in the through hole of the circuit board; a connecting element electrically connecting the circuit board and the semiconductor chip; an epoxy molding compound (EMC) covering the semiconductor chip and the connecting element; an external connecting terminal which is electrically connected to at least one side of the circuit board; and a supporter attached to a lower surface of the semiconductor chip and having a thermal expansion coefficient substantially equal to or greater than a thermal expansion coefficient of the EMC.

According to still another aspect of the present invention, there is provided a method of manufacturing an ultra thin semiconductor package, the method comprising providing a circuit board in which a through hole is formed; attaching a closure member to a lower surface of the circuit board, thereby covering the through hole; forming a supporter on an upper surface of the closure member; attaching a semiconductor chip having an input/output pad in its upper edge to an upper surface of the supporter; electrically connecting the input/output pad of the semiconductor chip and the circuit board; forming an epoxy molding compound (EMC) that covers at least part of the semiconductor chip, and the circuit board; attaching a solder ball to the lower surface of the circuit board; and removing the closure member, where a thermal expansion coefficient of the supporter is substantially equal to or greater than a thermal expansion coefficient of the EMC.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

FIG. 1 is a cross-sectional view of a conventional semiconductor package having a through hole;

FIG. 2 is a cross-sectional view of an ultra-thin semiconductor package having a through hole according to a first embodiment of the present invention;

FIG. 3 is a cross-sectional view of an ultra-thin semiconductor package according to a second embodiment of the present invention;

FIG. 4 is a cross-sectional view of an ultra-thin semiconductor package according to a third embodiment of the present invention;

FIG. 5 is a cross-sectional view of an ultra-thin semiconductor package according to a fourth embodiment of the present invention;

FIG. 6 is a cross-sectional view of a stacked semiconductor package using ultra-thin semiconductor packages according to a fifth embodiment of the present invention; and

FIGS. 7A through 7F are cross-sections illustrating a method of manufacturing an ultra-thin semiconductor package according to a sixth embodiment of the present invention.

DETAILED DESCRIPTION

The present invention will now be described more fully with reference to the accompanying drawings in which exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. In the drawings, the forms of the elements are exaggerated for clarity. To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements.

FIG. 2 is a cross-section of an ultra-thin semiconductor package having a through hole according to a first embodiment of the present invention.

Referring to FIG. 2, a semiconductor package 200 comprises a circuit board 110 having a first surface 110 a and a second surface 110 b. The circuit board 110 is formed of a resin board 105, for instance, BT (mismaleimide triazine). A through hole 115 is formed in a predetermined portion of the circuit board 110. A circuit pattern 120 is formed in upper and lower portions of the circuit board 110 as well as through the circuit board 110. The circuit pattern 120 includes a bond finger 120 a, ball lands 120 b, and a stud 120 c. The bond finger 120 a is disposed near the through hole 115 and is formed of an Au, Ag, or metal layer. In addition, the bond finger 120 a may be formed selectively on the first surface 110 a or the second surface 110 b of the circuit board 110. The ball lands 120 b include upper and lower ball lands, which are respectively formed on the first surface 110 a and the second surface 110 b of the circuit board 110. The upper and lower ball lands 120 b, disposed opposite each other across the circuit board 110, are formed of Au, Ag, Ni, or Pd. The stud 120 c electrically connects the corresponding upper and lower ball lands 120 b.

A protection layer 125 covers the first and second surfaces 110 a and 110 b of the circuit board 110. The protection layer 125, formed of an insulating layer, protects the circuit pattern 120 from an external environment and prevents a short between the circuit patterns 120. However, the ball lands 120 b that are exposed and contact the external connecting terminal should not be covered by the protection layer 125.

A supporter 130, which has a square or tiled shape, is located in the through hole 115 and a semiconductor chip 140 is attached to an upper portion of the supporter 130 by an adhesive bonding layer 135.

The semiconductor chip 140 has a first surface 140 a in which an input/output pad 145 is formed and a second surface 140 b to which the supporter 130 is attached. The input/output pad 145 is formed at an edge of the first surface 140 a of the semiconductor chip 140. In addition, the input/output pad 145 may be electrically connected to the bond finger 120 a by a connecting element 150 formed of one of Au and Al or a lead extended from the bond finger 120 a.

The semiconductor chip 140, the connecting element 150, and the first surface 110 a of the circuit board 110 are sealed by an epoxy molding compound (EMC) 160. The EMC 160 may be a resin material.

The supporter 130, to which the semiconductor chip 140 is attached, prevents warpage of the semiconductor chip 140 and the EMC 160 due to the difference between thermal expansion coefficients of the EMC 160 and the semiconductor chip 140. The supporter 130 may be formed of a resin or Cu foil having a thermal expansion coefficient equal to or 1 to 10 times larger than that of the EMC 160 and having a thickness of 10 to 50 μm. It is preferable that the supporter 130 and the EMC 160 have the same thermal expansion coefficient. However, a material having a thermal expansion coefficient larger than that of the EMC 160 is more preferably used for the supporter 130 since the size and thickness of the supporter 130 are relatively smaller than the size and thickness of the EMC 160.

The supporter 130 should be formed in the through hole 115 in order to prevent the height of the semiconductor package 100 from increasing. For instance, if the supporter 130 occupies a predetermined region in a lower portion of the circuit board 110, the height of the semiconductor package 100 decreases by the thickness of the supporter 130. Therefore, the semiconductor package 100 is preferably located in the through hole 115.

Furthermore, the adhesive bonding layer 135 attaching the supporter 130 to the semiconductor chip 140 may be an adhesive sheet or paste and have a thickness to fully attach the supporter 130 and the semiconductor chip 140. The thickness of the adhesive bonding layer may be, for instance, a thickness of about 10 to 50 μm.

Solder balls 170, which are external connecting terminals, are attached to the lower ball lands 120 b which are formed in the second surface 110 b of the circuit board 110.

Referring to FIG. 3, the ultra-thin semiconductor package 300 includes a sidewall protection layer 126 on a sidewall of the through hole 115 of the circuit board 110. The sidewall protection layer 126 improves the adhesive strength between the circuit board 110 and the EMC 160. The sidewall of the through hole 115 may become uneven when forming the through hole 115 in the circuit board 110. If the sidewall of the through hole 115 is uneven, the circuit board 110 and the EMC 160 may be lifted. Therefore, the sidewall protection layer 126 having a smooth surface is formed in the sidewall of the through hole 115, and the adhesive strength between the circuit board 110 and the EMC 160 is improved. In addition, the sidewall protection layer 126 may be further connected to the protection layer 125 formed in the first surface 110 a or the second surface 110 b of the circuit board 110.

Referring to FIG. 4, instead of the EMC 160 that covers the entire first surface 110 a of the circuit board 110, an EMC 161 may be formed to occupy part of the circuit board 110. In this case, the protection layer 125 may be partly removed to expose the upper ball lands 120 b which are formed in the first surface 110 a of the circuit board 110.

Referring to FIG. 5, the supporter 130 may be disposed near the first surface 110 a of the circuit board 110. In this case, the adhesive bonding layer 135 and the semiconductor chip 140 are sequentially attached to a lower surface of the supporter 130 and the bond finger 120 a is located at the second surface 110 b of the circuit board 110. The input/output pad 145 of the semiconductor chip 140 is electrically connected to the bond finger 120 a by the connecting element 150.

Furthermore, a stacked semiconductor package may be formed by stacking several ultra thin semiconductor packages.

Referring to FIG. 6, the stacked semiconductor package 600 comprises a plurality of stacked unit packages 100 a, 100 b, 100 c and 100 d. The unit packages 100 a, 100 b, 100 c and 100 d may have the same structures. In addition, the unit packages 100 a, 100 b, 100 c and 100 d may include the semiconductor chip 140, the connecting element 150, and the EMC 161 partly covering the circuit board 110. That is, the semiconductor package, 400 and 500 of FIGS. 4 and 5 may be used.

The protection layer 125 expose the upper and lower ball lands 120 b of the circuit board 110 of each of the unit packages 100 a, 100 b, 100 c and 100 d such that the unit packages 100 a, 100 b, 100 c and 100 d are electrically connected. Furthermore, the upper ball lands 120 b formed on the first surface 110 a and the lower ball lands 120 b formed on the second surface 110 b in the circuit board 110 of the unit packages 100 a, 100 b, 100 c and 100 d may be aligned.

In addition, the unit packages 100 a, 100 b, 100 c and 100 d are electrically connected by the solder balls 170, that is, the external connecting terminals. The solder balls 170, which are located between the upper and lower ball lands 120 b, electrically connect the stacked unit packages 100 a, 100 b, 100 c and 100 d. Here, it is preferable that a height H2 of the solder ball 170 is greater than a height H1 of the EMC 160, to allow for proper stacking and connection.

Therefore, by attaching the supporter 130, which has a thermal expansion coefficient similar to or larger than that of the EMC 160, to a lower surface of the semiconductor chip 140, the warpage of the semiconductor chip 140 caused by curing the EMC 160 and due to the difference in thermal expansion coefficients of the semiconductor chip 140 and the EMC 160, is reduced.

FIGS. 7A through 7F are cross-sectional views illustrating a method of manufacturing an ultra-thin semiconductor package according to a sixth embodiment of the present invention.

Referring to FIG. 7A, a resin board 105 is prepared. The resin board 105 has a first surface 110 a and a second surface 110 b on an opposite side of the resin board 105 as the first surface 110 a. Then, a circuit pattern 120, which is electrically connected to each of the first and second surfaces 110 a and 110 b of the resin board 105, is formed. The forming of the circuit pattern 120 will now be explained.

A metal layer formed of Au, Ag, or Pd is plated on the second surface 110 b of the resin board 105 and then a predetermined portion of the metal layer is etched to form lower ball lands 120 b. In order to expose the lower ball lands 120 b, a via hole (not shown) is formed by etching a predetermined portion of the resin board 105 and then a stud 120 c is formed in the resin board 105 by filling a conductive layer inside the via hole. After plating the metal layer on the second surface 110 b of the resin board 105, upper ball lands 120 b and a bond finger 120 a are formed by etching a predetermined portion of the metal layer in order for the metal layer and the stud 120 c to contact. Here, the processes of forming the upper and lower ball lands are interchangeable. A circuit board 110 is completed by the formation of the bond finger 120 a, the ball lands 120 b and the stud 120 c.

A through hole 115 is formed in a predetermined portion of the circuit board 110 according to the method explained above. It is preferable that the through hole 115 has a size larger than that of a semiconductor chip 140 that will be attached to the through hole later. Here, the order of forming the circuit pattern 120 and the through hole 115 can be reversed.

Thereafter, a protection layer 125, for instance, a resin or insulating layer, is formed on each of the first and second surfaces 110 a and 110 b of the circuit board 110. Then, a predetermined portion of the protection layer 125 may be removed in order to expose the bond finger 120 a and the upper and lower ball lands 120 b. If the EMC 160 is formed on the whole surface of the circuit board 110, as in the ultra-thin semiconductor package 200 illustrated in FIG. 2, it is preferable that only portions of the protection layer 125 formed on the bond finger 120 a and formed on the lower ball lands 120 b are removed. In addition, in the ultra-thin semiconductor package 200 as illustrated in FIG. 3, a sidewall protection layer 126 may be formed on a sidewall of the through hole 115. The sidewall protection layer 126 may be formed in the same process as the forming the protection layer 125.

Referring to FIG. 7B, a closure member 128 is attached to the second surface 110 b of the circuit board 110 in order to cover the through hole 115. The closure member 128 may be slightly larger than the through hole 115 or be attached to the whole first surface 110 a of the circuit board 110. The closure member 128 is formed of an insulating layer or an ultraviolet tape that can be exfoliated by ultraviolet rays. Then, a supporter 130 is attached to an upper surface of the closure member 128. It is preferable that the supporter 130 has a thermal expansion coefficient equal to or 1 to 10 times larger than that of an EMC which will be formed hereafter. In addition, the supporter 130 may have a square shape and be built in the through hole 115. A liquid material such as a resin material may be spread on the upper surface of the closure member 128 and is subsequently cured to form the supporter 130.

Referring to FIG. 7C, after placing an adhesive bonding layer 135 with a thickness of 10 to 30 μm on an upper surface of the supporter 130, a semiconductor chip 140 is attached to the upper surface of the supporter 130. The adhesive bonding layer 135 may be an adhesive sheet or paste. If the supporter 130 is formed of a resin material, the semiconductor chip 140 can be attached directly to the upper surface of the supporter 130 without interposing the adhesive bonding layer 135. The semiconductor chip 140 has a first surface 140 a on which an input/output pad 145 is disposed and a second surface 140 b is attached to the upper surface of the supporter 130 such that the first surface 140 a is directed upwards.

Referring to FIG. 7D, the input/output pad 145 of the semiconductor chip 140 and the bond finger 120 a, which is located at an edge of the through hole 115, are connected by a wire 150.

Referring to FIG. 7E, in order to protect the semiconductor chip 140 and the wire 150, a resin material is spread on a predetermined portion of the first surface 110 a of the circuit board 110 and an EMC 161 is formed by carrying out a curing process with respect to the resin material at a predetermined temperature. As illustrated, the EMC 161 is formed to cover the semiconductor chip 140, the wire 150, and part of the circuit board 110. However, as in the ultra-thin semiconductor package 200 illustrated in FIG. 2, the EMC 161 may be formed on the entirety of the first surface 110 a of the circuit board 110.

Referring to FIG. 7F, an external connecting terminal 170, for instance, a solder ball, is attached to the second surface 110 b of the circuit board 110 such that the external connecting terminal 170 contacts the respective ball lands 120 b. Then, the circuit board 110 is separated into respective unit packages by a singulation tool such as a saw, and thereafter the closure member 128 is removed from the lower surface of the supporter 130. The process of separating the closure member 128 may be performed prior to the separating of the circuit board 110. Thus, the ultra-thin semiconductor package is completed.

As described above, the ultra thin semiconductor package having a built-in semiconductor chip according to exemplary embodiments of the present invention includes a supporter with a thermal expansion coefficient substantially equal to or greater than that of an EMC and is attached to a lower portion of the EMC in order to improve warpage of the semiconductor chip resulting from a the difference in thermal expansion coefficients between the semiconductor chip and the EMC.

Thus, when curing the EMC, a contraction rate of the EMC is offset by that of the supporter, and, bending of the semiconductor chip and the EMC, that is the warpage, is prevented.

The height of the ultra-thin semiconductor package does not increase since warpage of the semiconductor package is prevented. Furthermore, the supporter is formed in the through hole of the circuit board, and thus, the height of the ultra-thin semiconductor package does not increase. In addition, cracks caused by warpage are also prevented.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. 

1. A method of manufacturing a semiconductor package, the method comprising: forming a circuit board; forming a through hole in the circuit board; attaching a closure member to a lower surface of the circuit board, thereby covering the through hole; forming a supporter on an upper surface of the closure member; attaching a semiconductor chip to an upper surface of the supporter, the chip having an input/output on its upper edge; electrically connecting the input/output pad of the semiconductor chip and the circuit board; forming an epoxy molding compound (EMC) that covers at least part of the semiconductor chip, and the circuit board; attaching a solder ball to the lower surface of the circuit board; and removing the closure member.
 2. The method of claim 1, wherein the forming the circuit board includes: preparing a resin board having a first surface and a second surface on an opposite side of the resin board; forming a first circuit pattern in the first surface of the resin board; etching the resin board to form a via hole therethrough and to expose the first circuit pattern; forming a conductive stud in the via hole; and forming a second circuit pattern in contact with the conductive stud on the second surface of the resin board.
 3. The method of claim 2, wherein forming a through hole occurs before forming the first circuit pattern in the first surface of the resin board or after forming the second circuit pattern.
 4. The method of claim 2, wherein the closure member is an insulating or ultraviolet tape.
 5. The method of claim 2, wherein the forming of the supporter comprises: preparing a square plate smaller than the through hole; and attaching the plate to an upper portion of the supporter with an adhesive.
 6. The method of claim 2, wherein the forming of the supporter includes: coating a liquid material used for a supporter on the upper surface of the closure member; and curing the liquid material to be a square shape.
 7. The method of claim 2, wherein the forming of the EMC includes: coating a resin material on an upper portion of the semiconductor chip, the connecting element, and the circuit board; and curing the resin material. 